SE1150562A1 - Process of an HC dosing system and an HC dosing system - Google Patents

Abstract

SUMMARY The invention relates to a method of an HC dosing system, wherein liquid fuel is supplied to a supply device (230), by means of which fuel is supplied to at least one consumption point (250) from a container (205), comprising the step of continuously detecting the supply pressure ( P) provides the feed device (230). The method also includes the step of controlling the operation of the supply device (230) on the basis of changes (P ') of said supply pressure (P) in order to reduce the effect of unwanted air supply of the supply device (230). The invention also relates to a computer program product comprising program code (P) for a computer (200; 210) for implementing a method according to the invention. The invention also relates to an HC dosing system and a motor vehicle (100) equipped with the HC dosing system. Figure 2 for publication

Description

back to the container. According to this configuration, it is possible to cool the dosing unit by means of said diesel which, when cooled, flows from the container via the pump and the dosing unit back to the container. In this way an active cooling of the dosing unit is provided. The return flow from the dosing valve to the container is today substantially constant.

Under certain conditions, air can enter the DPF system upstream of the pump. This can e.g. take place at start-up of the DPF system after initial installation thereof. In this case, air is present in the suction hose. Furthermore, air can enter the suction hose when the DPF system has used all available fuel in the separate container, the container being empty of fuel. In this case, the pump sucks dry, whereby air is sucked into the pump via the suction hose.

According to another example, air can enter the suction hose in situations where there is a limited amount of fuel left in the separate container in the DPF system and said DPF system moves in such a way that ripples occur in the container. In this case, air can be sucked into the pump via the suction hose.

According to a further example, the suction hose may be incorrectly mounted to the pump, whereby an air leakage occurs on the upstream side of the pump. Also in this case, air can be sucked into the pump via the suction hose or in the event of a defective or damaged seal between the suction hose and the pump.

According to one example, the suction hose itself may be broken or defective in a manner that causes air to be sucked into the pump via the suction hose.

In cases where air enters the pump on a suction side thereof, the fuel flow in the DPF system is adversely affected, thereby reducing a cooling effect of the dosing unit with the potential risk of overheating of temperature sensitive components of the dosing unit as a result.

Furthermore, a regeneration of the particulate filter of the DPF system can be adversely affected by the presence of air in the pump due to the supply of the fuel to the oxidation catalyst being restricted, the temperature thereby falling. In such a case, it will take longer to perform a desired regeneration. It will also be more difficult in such a case to control a temperature of the DPF system.

In the presence of air in the pump in the DPF system, a working pressure of the dosing unit is adversely affected. Furthermore, today it takes quite a long time to build up a normal working pressure of the DPF system in the presence of air in the pump.

Since the dosing unit is currently arranged at the exhaust system of the vehicle, which exhaust system during operation of the vehicle is heated depending on e.g. load on the engine, the dosing unit risks overheating. Overheating of the dosing unit may result in degradation of the same consideration functionality, which may result in a degraded performance thereof.

The dosing unit today comprises electrical components, some of which include a circuit board. Said circuit boards can e.g. be provided for controlling the dosing of diesel to the exhaust system of the vehicle. These electrical components are sensitive to high temperatures for several reasons. Excessive temperatures of the dosing unit can result in degradation of the electrical components, which can lead to costly repairs at a service workshop. Furthermore, diesel present in the dosing unit can at least partially change to solid form at too high temperatures, which can lead to clogging of the dosing unit. According to one example, said diesel in the dosing unit undergoes pyrolysis, said diesel being at least partially converted to coke. Thus, at least a part of said can cook. diesel It is therefore of the utmost importance that the temperature of the dosing unit of the DPF system does not exceed a critical temperature.

Thus, there is a need to improve the present DPF system to reduce or eliminate the above mentioned disadvantages.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new and advantageously improved HC dosing system. An object of the present invention is to provide a new and advantageous method for improving the performance of a DPF system.

Another object of the invention is to provide a new and advantageous HC dosing system and a new and advantageous computer program for improving the performance of an HC dosing system.

Another object of the invention is to provide a new and advantageous DPF system and a new and advantageous computer program for improving the performance of a DPF system.

An object of the present invention is to provide a new and advantageous method for improving regeneration of a particle filter of an HC dosing system in the presence of air in said HC dosing system.

A further object of the invention is to provide an alternative method of an HC dosing system and an alternative computer program of an HC dosing system and an alternative HC dosing system.

Another object of the invention is to provide a method of an HC dosing system in which an operating pressure of the fuel can build up more rapidly in the presence of air in a feeding device compared with the prior art.

These objects are achieved with a method in an HC dosing system, where liquid fuel is supplied to a feeding device, by means of which fuel is supplied to at least one point of consumption from a container, according to claim 1.

According to one aspect of the invention, there is provided a method of an HC dosing system, wherein liquid fuel is supplied to a feeder, by means of which fuel is supplied to at least one point of consumption from a container, comprising the step of continuously detecting the feed pressure produced by the feeder, and controlling the operation of the feeder. on the basis of changes in said supply pressure in order to reduce the effect of unwanted air supply of the supply device.

In this case, a working pressure of the fuel can be built up faster in the presence of air upstream supplied to a feeding device compared with known technology. changing the operation of the method may further comprise the step of the feeding device correlated with the changes of said feeding pressure. In this case, a working pressure of the fuel can be built up faster in the presence of air upstream supplied to a feeding device compared with known technology. In a case where the supply pressure drops due to air being supplied upstream of the supply device for various reasons, a speed of the pump can then also be reduced. In a case where the supply pressure increases, after having been temporarily reduced due to air being supplied upstream of the supply device for various reasons, a speed of the pump can then also be increased. In this case, the operation of the supply device can thus be changed in a correlated manner taking into account the changes of said supply pressure according to the invention.

Control of the operation of said feeding device can take place via a pump speed of the feeding device. Hereby an effective way is provided to control the feeding device according to an aspect of the invention. The term pump speed can also be called pump speed or pump frequency.

Control of the operation of said feeding device can take place against a predetermined level of the feeding pressure which the feeding device is intended to produce. This predetermined level refers to a predetermined working pressure at which the HC dosing system is intended to operate. Said predetermined level of the working pressure which the feeding device is intended to produce can be any suitable level. This provides a flexible solution that is easy to adapt to different types of HC dosing systems. This provides a versatile solution to the above-mentioned problems.

Control of the operation of said feeding device can take place on the basis of the time derivative of said detected feed pressure. By continuously observing the feeding device on the basis thereof, an efficient method of obtaining the time derivative of the feeding pressure and controlling the operation of according to the invention is achieved. The solution is not computationally heavy because a time derivative of the feed pressure is quick and easy to determine with dedicated computing means. In this case, a method is provided which can quickly adapt the control of the feeding device in the event of sudden changes in the feeding pressure caused by the presence of air in the feeding device.

The method may further comprise the steps of: - determining the presence of air upstream of the supply device, and - in determining such occurrence, controlling the operation of the supply device on the basis of changes in said supply pressure.

By thereby optimizing the start-up time of the HC dosing system in the presence of air supplied to the feeding device, regeneration of the DPF filter The HC dosing system can be used to supply a fuel to a DPF system. air of the feeding device is determined until a desired working pressure of HC- is improved and made more efficient in certain applications where With start-up time is meant a time from the time the presence of the dosing system has been achieved. According to one aspect of the invention, the start-up time may advantageously be less than e.g. 3 minutes.

The method may further comprise the step of: - determining said occurrence on the basis of detected operating power of a power source arranged to operate said feeding device and / or on the basis of a fixed time the feeding device has taken place. During which a deviating operation of By detecting a behavior of the feeding device, which behavior is characterized by the presence of air in the feeding device, the feeding device can be controlled according to the invention to thereby improve or optimize the start-up time of the HC dosing system.

The supply device may be a diaphragm pump. The feeding device can be any suitable pump, such as e.g. a gear pump.

Said at least one point of consumption may be a dosage unit.

To minimize the influence of air or air bubbles on the HC dosing system, the innovative method can be used to continuously adapt an operating effect of the feeding device to a prevailing situation, in particular taking into account the time derivatives of the feeding pressure of the feeding device. As an effect with the better average efficiency of the feeding device in the presence of air of the positive innovative method, the same can be achieved.

The procedure is easy to implement in existing motor vehicles. Software in an HC dosing system, where fuel is supplied to a feeding device, by means of which fuel is supplied to at least one consumption point from a container according to the invention, can be installed in a control unit of the vehicle in the manufacture thereof. A buyer of the vehicle can thus be given the opportunity to choose the function of the procedure as an option. Alternatively, software comprising performing it in an HC dosing system, where fuel is supplied to a feeding device, by means of which fuel is supplied to at least one point of consumption from a container, is installed in a control unit of the vehicle when upgrading at a service station. In this case program code for that innovative procedure, the software can be loaded into a memory in the controller. Implementing the innovative procedure is thus cost-effective, especially since no additional sensors or components need to be installed in the vehicle.

The required hardware is already present in the vehicle today.

The invention thus provides a cost-effective solution to the above problems.

Software comprising program code in an HC dosing system, in which liquid fuel is supplied to a feeding device, by means of which fuel is supplied to at least one point of consumption from a container, can be easily updated or replaced. Furthermore, different parts of the software comprising program code in an HC dosing system, where liquid fuel is supplied to a feeding device, by means of which fuel is supplied at least one point of consumption from a container can be exchanged independently of each other. This modular configuration is advantageous from a maintenance perspective.

According to one aspect of the invention, there is provided an HC dosing system arranged to supply liquid in liquid form to a feeding device, which feeding device is arranged to supply fuel to at least one point of consumption from a container, comprising: detecting what the feeding device produces, and means for continuously supplying pressure. means for controlling the operation of the feeding device on the basis of changes in said feeding pressure in order to reduce the effect of unwanted air supply of the feeding device.

The HC dosing system may further comprise means for changing the operation of the feeding device correlated with the changes of said feeding pressure.

In the HC dosing system, control of the operation of said feeding device can take place via a pump speed of the feeding device. the operation of the feeding device takes place against a predetermined level of the feeding pressure which In the HC dosing system, control of said feeding device can be intended to achieve. The operation of the supply device takes place on the basis of the time derivative of said detection. In the HC dosing system, control of said supply pressure can be controlled.

The HC dosing system may further comprise: determining the presence of the air supply device, and in determining such occurrence, the supply device on the basis of changes in said supply pressure. means for supplying upstream - means for controlling the operation of the HC dosing system may further comprise: - means for determining said occurrence on the basis of detected operating power of a power source arranged to operate said feeding device and / or on the basis of a determined time during which a deviating operation of the feeding device took place.

The supply device may be a diaphragm pump. Said at least one point of consumption may be a dosage unit.

The above objects are also achieved with a motor vehicle comprising the HC dosing system. The motor vehicle can be a truck, bus or car.

According to one aspect of the invention, there is provided a computer program in an HC dosing system, wherein liquid fuel is supplied to a feeding device, by means of which fuel is supplied to at least one consumption point from a container, said computer program comprising program code stored on a computer readable medium for cause an electronic control unit or another computer connected to the electronic control unit, to perform the steps according to any one of claims 1-9.

According to one aspect of the invention, there is provided a computer program in an HC dosing system, in which liquid liquid is supplied to a feeding device, by means of which fuel is supplied to at least one point of consumption from a container, said computer program comprising program code for causing an electronic control unit or another computer connected to the electronic control unit, to perform the steps according to any one of claims 1-9.

According to one aspect of the invention, there is provided a computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-9, when said computer program is run on an electronic control unit or another computer connected to the electronic control unit. .

Additional objects, advantages and novel features of the present invention will become apparent to those skilled in the art from the following details, as well as through the practice of the invention. While the invention is described below, it should be understood that the invention is not limited to the specific details described. Those skilled in the art having access to the teachings herein will recognize and incorporate within other further applications, modifications areas, which are within the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS 11 For a more complete understanding of the present invention and further objects and advantages thereof, reference is now made to the following detailed description which is to be read in conjunction with the accompanying drawings in which like reference numerals refer to like parts in the various figures, and in which: Figure 1 schematically illustrates a vehicle, according to an embodiment of the invention; Figure 2 schematically illustrates a subsystem of the vehicle shown in Figure 1, according to an embodiment of the invention; Figure 3a schematically illustrates a flow chart of a method, according to an embodiment of the invention; Figure 3b schematically illustrates in further detail a flow chart of a method, according to an embodiment of the invention; Figure 4a schematically illustrates a diagram where supply pressure is indicated as a function of time; Figure 4b schematically illustrates a diagram where pump speed is given as a function of time; and illustrating a computer, Figure 5 schematically according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE FIGURES Referring to Figure 1, a side view of a vehicle 100 is shown. The exemplary vehicle 100 consists of a tractor 110 with an engine 150 and a trailer 112. The vehicle may be a heavy vehicle, such as a truck or a bus. The vehicle can alternatively be a car.

It should be noted that the invention is suitable for use in any suitable HC dosing system and is thus not limited to DPF systems in motor vehicles. The innovative method and the innovative device according to an aspect of the invention are well suited for platforms other than an HC dosing system other than motor vehicles, such as e.g. watercraft. The watercraft can be of any kind, such as e.g. motorboats, ships, ferries or ships.

The innovative method and the innovative HC dosing system according to an aspect of the invention are also well suited for e.g. systems including industrial engines and / or motorized industrial robots.

The innovative method and the innovative HC dosing system according to an aspect of the invention are also well suited for different types of power plants, such as e.g. an electric power plant comprising a diesel generator.

The innovative process and the innovative HC dosing system are well suited for an arbitrary engine system that includes an engine and an HC dosing system, such as e.g. at a locomotive or other platform.

The innovative method and device are well suited for an arbitrary system that includes a particulate generator (eg, an internal combustion engine) and an HC dosing system.

The innovative method and the innovative device are well suited for an arbitrary system which includes an arbitrary system which generates exhaust gases with particles and a filter which stores particles, which particles are burned during a regeneration of said filters, in particular during an active regeneration of said filters. filter.

It should be noted that the HC dosing system can be any HC-HC dosing system in a DPF system of a vehicle. The delivery device dosing system, although exemplified herein as one, may be any feed device, and need not be a diaphragm pump as described herein. The fuel of the HC dosing system can be any fuel, such as e.g. oil, such as e.g. lubricating oil, diesel or other hydrocarbon-based fuel, such as e.g. gasoline, ethanol or methanol, etc.

Here, the term "link" refers to a communication link which may be a physical line, such as an optoelectronic communication line, or a non-physical line, such as a wireless connection, for example a radio or microwave link k.

Here, the term "conduit" refers to a passage for holding and transporting a fluid, such as e.g. a fuel in liquid form. The conduit can be a pipe of any suitable dimension. The conduit may consist of any suitable material, such as e.g. plastic, rubber or metal.

Herein, the term "fuel" refers to an agent used for the active regeneration of a particulate filter in an HC dosing system. Said fuel is according to one embodiment diesel. Of course, other types of hydrocarbon-based fuels can be used. Here, diesel is mentioned as an example of a fuel, but a person skilled in the art realizes that the innovative method and the innovative device can be realized for other types of fuels, with requirements such as e.g. adequate adjustments, adjustments to the boiling temperature of selected fuels, in control algorithms for executing software code in accordance with the innovative procedure. Although the term HC dosing system is used herein to indicate a particulate filter system, the invention is not limited to the use of a diesel particulate filter. On the contrary, other types of particle filters can be used according to the invention. One skilled in the art will recognize what kind of fuel is best suited for regenerating the selected particulate filter.

Referring to Figure 2, a subsystem 299 of the vehicle 100 is shown.

The subsystem 299 is arranged in the tractor 110. The subsystem 299 may form part of a HC dosing system, such as e.g. a DPF system. The subsystem 299 according to this example consists of a container 205 which is arranged to contain a fuel. The container 205 is arranged to contain a suitable amount of fuel and is further arranged to be able to be refilled if necessary.

The container can hold e.g. 200 or 1500 liters of fuel.

A first line 271 is arranged to lead the fuel to a pump 230 from the container 205. The pump 230 may be any suitable pump. The pump 230 may be a diaphragm pump comprising at least one filter. The pump 230 is arranged to be driven by means of an electric motor. The pump 230 is arranged to pump the fuel from the container 205 via the first line 271 and via a second line 272 supply said fuel to a dosing unit 250.

The dosing unit 250 comprises an electrically controlled dosing valve, by means of which a flow of fuel added to the exhaust system can be controlled. The pump 230 is arranged to pressurize the fuel in the second line 272.

The dosing unit 250 is provided with a throttling unit, against which said pressure of the fuel is built up in the subsystem 299. This pressure is referred to herein as the working pressure of the HC dosing system.

Dosing unit 250 is arranged to supply said fuel to a 100. Dosing unit 250 is arranged to supply in a controlled manner a suitable amount of exhaust system (not shown) to the vehicle. More specifically, fuel to an exhaust system of the vehicle 100. According to this embodiment, particulate filter (not shown) ) in the form of a DPF arranged downstream of a position of the exhaust system where the supply of the fuel is provided. The amount of fuel supplied to the exhaust system is intended to be used in a conventional manner for active regeneration of the particulate filter.

The dosing unit 250 is arranged at e.g. an exhaust pipe arranged to direct exhaust gases from the internal combustion engine 150 of the vehicle 100 to a particulate filter.

The dosing unit 250 is arranged in thermal contact with the exhaust system oxidation catalyst arranged upstream of said vehicle 100. This means that thermal energy is stored in e.g. an exhaust pipe, muffler, particle filter and a downstream SCR catalyst can then be led to the dosing unit. The dosing unit 250 comprises an electronic control card, which is 200.

The dosing unit 250 also comprises plastic and / or rubber components, arranged to handle communication with a control unit which may melt or be otherwise adversely affected at excessive temperatures.

The dosing unit 250 is sensitive to temperatures above a certain temperature value, such as e.g. 120 degrees Celsius. Since e.g. exhaust pipe, this temperature value there is a risk that the dosing unit 250 may overheat the muffler and the particulate filter of the vehicle 100 exceeds during operation of the vehicle or after operation of the vehicle unless cooling thereof is achieved.

A third conduit 273 is provided between the metering unit 250 and the container 205. The third conduit 273 is arranged to return a certain amount of the fuel supplied to the metering valve 250 to the container 205. With this configuration advantageous cooling of the metering unit 250 is provided. the metering unit 250 is cooled by a flow of the fuel as it is pumped through the metering unit 250 from the pump 230 to the container 205.

A first control unit 200 is arranged for communication with a pressure sensor 220 via a link 293. The pressure sensor 220 is arranged to detect a prevailing pressure of the fuel where the sensor is mounted. According to this embodiment, the pressure sensor 220 is arranged at the second line 272 to measure a working pressure of the fuel downstream of the pump 230. The pressure sensor 220 is arranged to continuously send signals to the first control unit 200 including information about a prevailing pressure of the fuel. The first control unit 200 is arranged for communication with the pump 230 via a link 292. The first control unit 200 is arranged to control operation of the pump 230 in order to e.g. regulate the flows of fuel within the subsystem 299.

The first control unit 200 is arranged to control an operating power of the pump 230 by controlling the electric motor thereby.

The first control unit 200 is arranged to determine a prevailing operating power of the electric motor of the pump, which operating power may change depending on the presence of air in the pump 230. In the event that air enters the first line 271, a supply current to the pump changes on the basis thereof. . The first control unit 200 is arranged to monitor the pump 230 in order to be able to determine a supply device. Similarly, the first control unit 200 behavior due to the presence of air in the device is arranged to monitor a working pressure of the fuel in order to be able to determine a behavior which depends on the presence of air in the feeding device.

The first control unit 200 is arranged for communication with the dosing unit 250 via a link 291. The first control unit 200 is arranged to control operation of the dosing unit 250 in order to e.g. regulate the supply of fuel to the exhaust system of the vehicle 100. The first control unit 200 is arranged to control the operation of the dosing unit 250 in order to e.g. regulate the re-supply of fuel to the tank 205.

According to one embodiment, the first control unit 200 is arranged to control the pump 230 in accordance with an aspect of the innovative method on the basis of the received signals comprising a prevailing pressure of the fuel at the area of the pressure sensor 220. In particular, the first control unit 200 according to an embodiment is arranged to control on the basis of the received signals comprising a prevailing pressure of the fuel at the area of the pressure sensor 220 operation of the pump 230 with reduced power compared to ordinary operation where an presence of air at the inlet of the pump 230 or in the pump 230, in accordance with one aspect of the innovative process.

According to one embodiment, the first control unit 200 is arranged to control said pump 230 in accordance with an aspect of the innovative method on the basis of the signals received from the pump 230, comprising information on a prevailing actual operating power of the pump 230. In particular, the first control unit 200 according to an embodiment is arranged to control on the basis of the received signals comprising a prevailing actual operating power of the pump 230 its operation with reduced power compared to ordinary operation where an presence of air is determined at the inlet of the pump 230 or in the pump 230, in accordance with one aspect of the innovative process.

A second control unit 210 is arranged for communication with the first control unit 200 via a link 290. The second control unit 210 may be detachably connected to the first control unit 200. The second control unit 210 may be a control unit external to the vehicle 100. The second control unit 210 may be arranged to perform the innovative method steps according to the invention. The second control unit 210 can be used to upload software to the first control unit 200, in particular software for performing the innovative method. The second control unit 210 may alternatively be arranged for communication with the first control unit 200 via an internal network in the vehicle. The second control unit 210 may be arranged to perform substantially similar functions as the first control unit 200, such as e.g. on the basis of the received signals comprising a prevailing pressure of the fuel at the area of the pressure sensor 220 control operation of the pump 230 with reduced power compared to ordinary operation in the presence of air at the pump 230. The innovative method can be performed by the first control unit 200 or the second control unit 210, or by both the first control unit 200 and the second control unit 210. 18 According to this embodiment, a compressed air source 260 is arranged to supply pressurized air to the dosing unit 250 via a line 261. The dosing unit 250 is arranged to use said supplied pressurized air to further atomize the fuel being dosed. The compressed air can also be used to at least partially drive the dosing unit to dose said fuel into the exhaust duct. The compressed air can also be used to, where applicable, blow out e.g. dosing unit 250. This can be done during operation of the motor 150, or after the motor 150 has been switched off.

According to one embodiment, the container 205 may be the vehicle's fuel tank, with parts of the vehicle's existing fuel system being used in accordance with the present invention. According to another example, the container may be a separate container, i.e. not the same container as the vehicle's fuel tank.

According to one embodiment, the dosing unit 250 is arranged directly at an exhaust duct of the HC dosing system. According to another example, the dosing unit 250 is provided with a passive nozzle presently provided through said exhaust duct for dosing said fuel directly into the exhaust duct.

According to one embodiment, said pump 230 is the same pump that normally generates fuel pressure for an injection system of the engine 150. According to another example, said pump 230 is a separate pump, i.e. not the same pump that normally generates the fuel pressure to the injection system.

According to one example, a precatalyst and / or oxidation catalyst is mounted in series with the particulate filter. In this case, said precatalyst and / or oxidation catalyst are arranged upstream of said particle filter.

Figure 3a schematically illustrates a flow chart of a process in an HC dosing system, where liquid fuel is supplied to a feeding device, by means of which fuel is supplied to at least one consumption point from a container, according to an embodiment of the invention. The method comprises a first method step s301. Step s301 includes the steps of continuously detecting the feed pressure produced by the feed device, and controlling the operation of the feed device based on changes in said feed pressure in order to reduce the effect of unwanted air supply to the feed device. After step s301, the process is terminated.

Figure 3b schematically illustrates a flow chart of a process in an HC dosing system, in which liquid fuel is supplied to a feeding device, by means of which fuel is supplied at least one consumption point from a container, according to an embodiment of the invention.

The method includes a first method step s310. The process step s310 includes the step of starting operation of the pump 230. After the process step s310, a subsequent process step s320 is performed.

The method step s320 includes the step of determining a number of values for at least one operating parameter. This operating parameter can e.g. be a prevailing supply pressure P of the fuel of the HC dosing system downstream of the pump 230. Another operating parameter may be an actual prevailing operating power of the pump 230. After the process step s320, a subsequent process step s330 is performed.

The method step s330 includes the step of determining on the basis of the values of the at least one parameter whether a first condition is fulfilled. The first condition may be a condition characterized by the presence of air in the pump 230. The first condition may be a condition involving the presence of air supplied to the pump 230. According to one example, it may be determined that the first condition is met if a prevailing supply pressure of the fuel of the HC dosing system begins to drop from a prevailing level. According to another example, it can be determined that the first condition is satisfied if an actual prevailing operating power of the pump 230 is changed from a value representing an operating power of the pump 230 during ordinary operation to a value below a predetermined value. If the first condition is met, a subsequent step s340 is performed.

Alternatively, the first state can be determined if a character change of the first order time derivative of the feed pressure can be determined, indicating that the feed pressure drops. According to one example, the first state can be determined if the second order time derivative of the feed pressure is equal to zero (0), indicating that the feed pressure neither increases nor decreases. According to one example, the first state can be determined if a character change from positive to negative of the second order time derivatives is determined, indicating that the supply pressure from an increase begins to decrease.

If the first condition is not satisfied, the step s310 is performed again.

According to one embodiment, the process steps s310-s330 are optional, ie according to an example, the innovative process can start with the process step s340 described below.

Method step s340 includes the step of determining a value for the feed pressure P of the fuel downstream of the pump 230. This may be done by means of the pressure sensor 220. The pressure sensor 220 is arranged to send a signal including information about a prevailing feed pressure P of the fuel downstream of the pump 230 to the first control unit 200. the process step s340 performs a subsequent process step s350.

The method step s350 includes the step of determining a value for the first order time derivative P 'of the feed pressure P determined in step s340.

Determination of the first order time derivatives P 'can take place by means of the first control unit 200. After the process step s350, a subsequent step s360 is performed. The operation step comprises the step of controlling in order to reduce the effect of unwanted air supply of the pump 230. Hereby a pump speed of the pump 230 is adjusted on the basis of the value of said first order time derivative P 'of the feed derivative P' of the supply pressure P. P, according to one aspect of the invention. After the process step S360, a process step s370 is performed.

Process step S360 includes the step of determining whether or not to end the process. If it is determined that the procedure is to be terminated, this is done. If it is determined that the process is not to be terminated, process step S340 is performed again, making it possible to continuously control a pump speed of the pump 230 on the basis of changes in the feed pressure P of the fuel, the pump 230 of the HC dosing system is depressed.

According to the invention, it is possible with the described adaptive method to relatively quickly regain a desired operating pressure of the HC dosing system by controlling the pump speed of the pump 230 on the basis of changes in the supply pressure as above, in particular in the presence of air in the pump 230.

Figure 4a schematically illustrates a diagram where the feed pressure P of the fuel time T. The HC dosing system is arranged to be operated at a predetermined feed pressure Pshould (the desired operating pressure of the HC dosing system). At the start of operation of the pump 230, the supply pressure increases downstream of the pump 230 until a downstream pump 230 is specified as a function of time T1 where unwanted air enters the pump 230. Thereby the pressure drops to a second time T2 where the pump is again able to start building up the supply pressure. . At a third time T3, air enters the pump 230 again, the feed pressure decreasing until a fourth time T4, where the pump is again able to start building up the feed pressure to a desired operating pressure Pshould. Figure 4b schematically illustrates a diagram in which pump speed PV of the pump 230 is indicated as a function of time T. It should be noted that the first control unit 200 is arranged to continuously determine the first order time derivative P 'of the values of the supply pressure P which are continuously detected. The first control unit 200 is also arranged to determine the second-order time derivative P "of the values of the supply pressure P which are continuously detected. At time T1 it can be determined that air has entered the pump 230. This can be done in different ways. According to one example, a character change of the first order time derivative can be determined, indicating that the supply pressure drops. According to one example, it can be determined that the second order time derivative is equal to zero (0), which indicates that the supply pressure neither increases nor decreases. According to one example, a character change from positive to negative of the second order time derivatives can be determined, indicating that the supply pressure from an increase begins to decrease.

Based on a magnitude of the first order time derivative of the supply pressure P, the first control unit 200 can control the pump speed PV of the pump 230.

According to a preferred example, the first control unit 200 can control the pump speed PV of the pump 230 on the basis of a magnitude of the first order time derivatives P 'of the feed pressure P in a correlated manner, i.e. if the feed pressure P drops at a certain speed, a pump speed can be lowered accordingly . Congruently, the first control unit 200 can control the pump speed PV of the pump 230 on the basis of a magnitude of the first order time derivatives P 'of the supply pressure P in a correlated manner as the supply pressure increases, i.e. if the supply pressure P increases at a certain speed, a pump speed can be increased way.

The diagram shows that the pump speed PV is controlled on the basis of changes in the supply pressure P until a desired working pressure Pshould is reached.

It appears that the pump speed PV is lowered until the time T1. It can be seen that the pump speed PV is relatively low between the first time T1 and the second time T2. It can be seen that the pump speed PV increases after the time T2 when the supply pressure P begins to increase and is then lowered to a relatively low level at the third time T3. It can be seen that the pump speed PV is relatively low between the third time T3 and the fourth time T4. It can be seen that the pump speed PV increases after the time T4 when the supply pressure P begins to increase and then decreases again to a suitable arbitrary level when the supply pressure P stabilizes.

According to one example, the curve of the pump speed PV follows relatively well the shape of a curve of the first order derivatives P 'of the feed pressure P. This means that a main principle of the invention is that the faster the feed pressure P rises, the higher the pump speed PV. Correspondingly, the pump speed PV is reduced on the basis of how fast the supply pressure drops. During a pressure drop of the supply pressure P, the pump speed PV is relatively low.

The pump speed can be controlled in any suitable manner on the basis of the first-order time derivative of the feed pressure P. An adaptive control of the pump speed of the pump is achieved in order to effectively build up the feed pressure of the HC dosing system to a desired level in the presence of air. of the pump 230, according to one aspect of the invention.

As a positive effect, the innovative method makes it possible to shorten a time interval between two peaks of the supply pressure, e.g. time period T3-T1.

This means that the desired working pressure Pshould can build up faster than in the prior art where the presence of air in the pump 230 is present.

Referring to Figure 5, there is shown a diagram of an embodiment of a device 500. The controllers 200 and 210 described with reference to Figure 2 may in one embodiment include the device 500. The device 500 includes a non-volatile memory 520, a data processing unit 510, and a read / write memory 550. The non-volatile memory 520 has a first memory portion 530 in which a computer program, such as an operating system, is stored to control the operation of the device 200 and / or 210. Furthermore, the device 500 comprises a bus memory. controller, a serial communication port, I / O means, an A / D converter, a time and date input and transfer unit, an event counter and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory portion 540.

A computer program P is provided which includes routines for continuously supplying a fuel delivery device to the HC metering system by means of which fuel is supplied to the HC dosing system, at least one consumption point from a container of a change in a continuously detected feed pressure of the fuel downstream of the pump. 230 in the HC dosing system in order to reduce the effect of unwanted air supply on the feeding device.

Program P includes routines for continuously controlling a pump speed of the pump based on time derivative values of a continuously detected feed pressure of fuel downstream of pump 230 in the HC metering system in order to reduce the impact of unwanted air supply to the feeder. routines for changing the operation of the Program P include the feeding device correlated with the changes of said feeding pressure, in accordance with the innovative method.

The program P includes routines for controlling the operation, e.g. by influencing a prevailing pump speed, of said feeding device against a predetermined level of the feeding pressure which the feeding device is intended to produce.

Program P includes routines for determining the presence of air upstream of the feed device, and upon determining such occurrence, controlling the operation of the feed device based on changes in the continuously detected feed pressure of fuel downstream of the pump 230 of the HC metering system.

The program P can be stored in an executable manner or in a compressed manner in a memory 560 and / or in a read / write memory 550.

When it is described that the data processing unit 510 performs a certain function, it is to be understood that the data processing unit 510 performs a certain part of the program which is stored in the memory 560, or a certain part of the program which is stored in the read / write memory 550.

The data processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 511. the data processing unit 510 via a data bus 514. To the data port 599, e.g. links 290, 292 and 293 are connected (see Figure 2).

The read / write memory 550 is arranged to communicate with When data is received on the data port 599, it is temporarily stored in the second memory part 540. When the received input data has been temporarily stored, the data processing unit 510 is prepared to perform code execution in a manner described above. According to one embodiment, signals received at the data port 599 include information about the actual operating power of the pump 230. According to one embodiment, signals received at the data port 599 include information about a feed pressure of the fuel. Said feed pressure is a prevailing feed pressure downstream of the pump 230. The received signals on the data port 599 may be used by the device 500 to determine the presence of air supplied to the pump 230, and at determined occurrence, control the operation of the feed device based on changes in said feed pressure. reduce the impact of unwanted air supply on the feeder. Parts of the methods described herein may be performed by the device 500 by means of the data processing unit 510 running the program stored in the memory 560 or the read / write memory 550. When the device 500 runs the program, the methods described herein are executed.

The foregoing description of the preferred embodiments of the present invention has been provided for the purpose of illustrating and describing the invention. It is not intended to be exhaustive or to limit the invention to the variations described. Obviously, many modifications and variations will occur to those skilled in the art. The embodiments were selected and described to best explain the principles of the invention and its practical applications, thereby enabling those skilled in the art to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims (22)

10 15 20 25 30 27 PATENT REQUIREMENTS A method of an HC dosing system, wherein liquid fuel is supplied to a supply device (230), by means of which fuel is supplied to at least one point of consumption (250) from a container (205), comprising the step of (s340) supply pressure (P) the supply device (230) ) causes, - continuously detects it as characterized by the step of: (s360) changes (P ') of said feed pressure (P) in order to reduce impact - control the operation of the feed device (230) on the basis of unwanted air supply of the feed device (230 ). The method of claim 1, further comprising the step of changing the operation of the feed device (230) correlated with the changes (P ') of said feed pressure (P). A method according to claim 1 or 2, wherein control of the operation of said feeding device (230) takes place via a pump speed (PV) of the feeding device. A method according to any one of the preceding claims, wherein control of the operation of said feeding device (230) takes place against a predetermined level (Pshould) of the feeding pressure which the feeding device is intended to produce. A method according to any one of the preceding claims, wherein control of the operation of said feed device (230) takes place on the basis of the time derivative (P ') of said detected feed pressure (P). A method according to any one of the preceding claims, further comprising the step of - determining (s330) the presence of air upstream of the supply device (230), and determining the operation (s360) of the supply device (230) on the basis of changes (P ') at the said - in such an occurrence, control at supply pressure (P). The method of claim 6, further comprising the step of: - determining (s330) said occurrence on the basis of detected operating power of a power source arranged to operate said feeding device and / or on which a deviating operation on the basis of a determined time during the feeding device occurred. A method according to any one of the preceding claims, wherein the feeding device is a diaphragm pump. A method according to any one of the preceding claims, wherein said at least one point of consumption (250) is a dosing unit (250). HC dosing system arranged to supply liquid in liquid form to a feeding device (230), which feeding device (230) is arranged to supply fuel to at least one consumption point (250) from a container (205), comprising: - means (220) for continuously detecting the feed pressure (P) produced by the feed device (230), characterized by - means (200; 210; 500) for controlling the operation of the feed device (230) on the basis of changes (P ') of said feed pressure (P) in purpose to reduce the effect of unwanted air supply to the feeding device. The HC dosing system of claim 10, further comprising means (200; 210; 500) for changing the operation of the feed device (230) correlated with the changes of said feed pressure (P). 10 15 20 25 30 29 HC dosing system according to claim 10 or 11, wherein control of the operation of said feeding device (P) takes place via a pump speed (PV) of the feeding device (230). HC dosing system according to any one of claims 10-12, wherein control of the operation of said feeding device takes place against a predetermined level (Pshould) of the feeding pressure which the feeding device is intended to produce. HC dosing system according to any one of claims 10-13, wherein control of the operation of said feeding device (230) takes place on the basis of the time derivative (P ') of said detected feed pressure (P). HC dosing system according to any one of claims 10 to 14, further comprising: - means (200; 210; 500) for determining the presence of air upstream of the supply device, and - means (200; 210; 500) for, when determined such occurrence, control the operation of the feed device (230) on the basis of changes (P ') of said feed pressure (P). The HC dosing system according to claim 15, further comprising: - means (200; 210; 500) for determining said occurrence on the basis of detected operating power of a power source arranged to operate said feeding device and / or on the basis of a fixed time. during which a deviating operation of the feeding device took place. HC dosing system claims 10-16, wherein according to one of the feeding device (230) is a diaphragm pump (230). The HC dosing system according to any one of claims 10 to 17, wherein said at least one consumption point (250) is a dosing unit (250). 10 15 20 30 A motor vehicle (100; 110) comprising an HC dosing system according to any one of claims 10-18. The motor vehicle (100; 110) according to claim 19, wherein the motor vehicle is something of a truck, bus or passenger car. A computer program (P) in an HC dosing system, wherein liquid fuel is supplied to a feeder (230), by means of which fuel is supplied to at least one point of consumption (250) from a container (205), the computer program (P) comprising program code for causing an electronic control unit (200; 500) or another computer (210; 500) connected to the electronic control unit (200; 500) for performing the steps according to any one of said claims 1-9. A computer program product comprising a program code stored on a computer readable medium for performing the method steps of any of claims 1-9, when said computer program is run on an electronic control unit (200; 500) or another computer (210; 500) connected to the electronic control unit (200; 500).